The goal of various non-repudiation schemes is essentially to provide proof that a message has been sent and received. In many cases, a third party (e.g., a central authority or arbitrator) is used to verify time stamps and digital signatures that serve to document the interaction between a message sender and a message receiver.
While several mechanisms to support non-repudiation have been developed, most of them burden the network with duplicative data transmission, and/or rely on extensive participation by the third party to the transaction. In addition, the third party may operate to store and maintain transaction records that will support verification efforts in the future, perhaps to resolve potential disputes.